Science (English Medium) कक्षा १२ - CBSE Question Bank Solutions for Chemistry

Why do physisorption and chemisorption behave differently with rise in temperature?

What is the role of activated charcoal in gas mask used in coal mines?

Give an example where physisorption changes to chemisorption with rise in temperature. Explain the reason for change.

What is the role of diffusion in heterogenous catalysis?

Assertion: Detergents with low CMC are more economical to use.

Reason: Cleansing action of detergents involves the formation of micelles. These are formed when the concentration of detergents becomes equal to CMC.

What is the role of adsorption in heterogenous catalysis?

Which of the following elements can be involved in pπ – dπ bonding?

On heating lead nitrate forms oxides of nitrogen and lead. The oxides formed are ______.

Name three oxoacids of nitrogen. Write the disproportionation reaction of that oxoacid of nitrogen in which nitrogen is in +3 oxidation state.

Assertion: \[\ce{HNO3}\] makes iron passive.

Reason: \[\ce{HNO3}\] forms a protective layer of ferric nitrate on the surface of iron.

On heating lead (II) nitrate gives a brown gas “A”. The gas “A” on cooling changes to colourless solid “B”. Solid “B” on heating with NO changes to a blue solid ‘C’. Identify ‘A’, ‘B’ and ‘C’ and also write reactions involved and draw the structures of ‘B’ and ‘C’.

Electronic configuration of a transition element X in +3 oxidation state is [Ar]3d⁵. What is its atomic number?

Metallic radii of some transition elements are given below. Which of these elements will have highest density?

Generally transition elements form coloured salts due to the presence of unpaired electrons. Which of the following compounds will be coloured in solid-state?

The magnetic nature of elements depends on the presence of unpaired electrons. Identify the configuration of transition element, which shows highest magnetic moment.

When \[\ce{KMnO4}\] solution is added to oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time because ______.

\[\ce{KMnO4}\] acts as an oxidising agent in acidic medium. The number of moles of \[\ce{KMnO4}\] that will be needed to react with one mole of sulphide ions in acidic solution is ______.

Interstitial compounds are formed when small atoms are trapped inside the crystal lattice of metals. Which of the following is not the characteristic property of interstitial compounds?

The magnetic moment is associated with its spin angular momentum and orbital angular momentum. Spin only magnetic moment value of \[\ce{Cr^{3+}}\] ion is ______.

Which of the following statements is not correct?